The jade plant--sometimes also known as the jade tree--is a member of the crassula family, a shrub-like succulent that makes an easy-to-care-for house plant. Jade plant starts rooted in water tend not to flourish, if they survive at all. The key to starting a thriving jade plant from a stem- or leaf-cutting off an old one is starting the new cutting in dry, sandy soil, in similar conditions to where the parent plant was grown.
Cut a healthy stem off the jade plant, just below a leaf node. You can also start a new jade plant from just one leaf of the old plant, but starting from a healthy stem gives the new plant a head start on its growth.
Leave the stem out in a well-ventilated area for about two weeks while the cut end dries out. If you're starting a jade plant from a leaf, go straight to step 3.
Fill a small pot with a mixture of one part sharp sand to two parts peat-free potting soil. Don't moisten the soil.
Pot the stem in the dry sandy soil. If you're starting the plant from a leaf, just set the cut or pinched-off end of the leaf on the sand, leaning the body of the leaf against the rim of the pot.
Position the new cutting near the parent plant, if possible, to ensure similar light conditions. Jade plants usually do best in a bright, sunny area with good air circulation.
Water the new jade plant only after two or three weeks have passed, or after roots have begun to show and a new plant is obviously forming around the leaf.